<template>
  <div
    class='xtx-carousel'
    @mouseenter="stop()"
    @mouseleave="start()"
  >
    <ul class="carousel-body">
      <li
        class="carousel-item"
        v-for="(item, inx) in siders"
        :key="item.id"
        :class="{fade: curIdx === inx}"
      >
        <RouterLink to="/">
          <img
            :src="item.imgUrl"
            alt=""
          >
        </RouterLink>
      </li>
    </ul>
    <a
      href="javascript:;"
      class="carousel-btn prev"
      @click="toggle(-1)"
    ><i class="iconfont icon-angle-left"></i></a>
    <a
      href="javascript:;"
      class="carousel-btn next"
      @click="toggle(1)"
    ><i class="iconfont icon-angle-right"></i></a>
    <div class="carousel-indicator">
      <span
        v-for="(i, inx) in 5"
        :key="i"
        :class="{ active: inx === curIdx}"
      ></span>
    </div>
  </div>
</template>

<script>
import { ref, onUnmounted, watch } from 'vue'
export default {
  name: 'XtxCarousel',
  props: {
    siders: { type: Array, default: () => [] },
    autoPlay: { type: Boolean, default: true }, // 是否自动播放
    duration: { type: Number, default: 1000 } // 间隔事件
  },
  setup (props) {
    const curIdx = ref(0) // 显示的图片
    let timer = '' // 定时器
    const autoPlayFn = () => {
      timer = setInterval(() => {
        curIdx.value++
        if (curIdx.value >= props.siders.length) curIdx.value = 0
      }, props.duration)
    }
    // 是否自动播放
    // if (props.autoPlay) { autoPlayFn() }
    watch(() => props.siders, (newValue, oldValue) => {
      if (newValue.length > 0 && props.autoPlay) {
        autoPlayFn()
      }
    })
    // 清除定时器
    onUnmounted(() => { clearInterval(timer) })
    // 鼠标移入事件
    const stop = () => {
      if (timer) clearInterval(timer)
    }
    // 鼠标移出事件
    const start = () => {
      if (props.siders.length && props.autoPlay) {
        autoPlayFn()
      }
    }
    // 上一张 下一张
    const toggle = (step) => {
      const newIndex = curIdx.value + step
      if (newIndex >= props.siders.length) {
        curIdx.value = 0
        return
      }
      if (newIndex < 0) {
        curIdx.value = props.siders.length - 1
        return
      }
      curIdx.value = newIndex
    }
    return { curIdx, stop, start, toggle }
  }
}
</script>
<style scoped lang="less">
.xtx-carousel {
  width: 100%;
  height: 100%;
  min-width: 300px;
  min-height: 150px;
  position: relative;
  .carousel {
    &-body {
      width: 100%;
      height: 100%;
    }
    &-item {
      width: 100%;
      height: 100%;
      position: absolute;
      left: 0;
      top: 0;
      opacity: 0;
      transition: opacity 0.5s linear;
      &.fade {
        opacity: 1;
        z-index: 1;
      }
      img {
        width: 100%;
        height: 100%;
      }
    }
    &-indicator {
      position: absolute;
      left: 0;
      bottom: 20px;
      z-index: 2;
      width: 100%;
      text-align: center;
      span {
        display: inline-block;
        width: 12px;
        height: 12px;
        background: rgba(0, 0, 0, 0.2);
        border-radius: 50%;
        cursor: pointer;
        ~ span {
          margin-left: 12px;
        }
        &.active {
          background: #fff;
        }
      }
    }
    &-btn {
      width: 44px;
      height: 44px;
      background: rgba(0, 0, 0, 0.2);
      color: #fff;
      border-radius: 50%;
      position: absolute;
      top: 228px;
      z-index: 2;
      text-align: center;
      line-height: 44px;
      opacity: 0;
      transition: all 0.5s;
      &.prev {
        left: 20px;
      }
      &.next {
        right: 20px;
      }
    }
  }
  &:hover {
    .carousel-btn {
      opacity: 1;
    }
  }
}
</style>
